godot-docs/classes/class_aescontext.rst

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.. DO NOT EDIT THIS FILE, but the AESContext.xml source instead.
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.. _class_AESContext:

AESContext
==========

**Inherits:** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`

Interface to low level AES encryption features.

Description
-----------

This class provides access to AES encryption/decryption of raw data. Both AES-ECB and AES-CBC mode are supported.


.. tabs::

 .. code-tab:: gdscript

    extends Node
    
    var aes = AESContext.new()
    
    func _ready():
        var key = "My secret key!!!" # Key must be either 16 or 32 bytes.
        var data = "My secret text!!" # Data size must be multiple of 16 bytes, apply padding if needed.
        # Encrypt ECB
        aes.start(AESContext.MODE_ECB_ENCRYPT, key.to_utf8())
        var encrypted = aes.update(data.to_utf8())
        aes.finish()
        # Decrypt ECB
        aes.start(AESContext.MODE_ECB_DECRYPT, key.to_utf8())
        var decrypted = aes.update(encrypted)
        aes.finish()
        # Check ECB
        assert(decrypted == data.to_utf8())
    
        var iv = "My secret iv!!!!" # IV must be of exactly 16 bytes.
        # Encrypt CBC
        aes.start(AESContext.MODE_CBC_ENCRYPT, key.to_utf8(), iv.to_utf8())
        encrypted = aes.update(data.to_utf8())
        aes.finish()
        # Decrypt CBC
        aes.start(AESContext.MODE_CBC_DECRYPT, key.to_utf8(), iv.to_utf8())
        decrypted = aes.update(encrypted)
        aes.finish()
        # Check CBC
        assert(decrypted == data.to_utf8())

 .. code-tab:: csharp

    using Godot;
    using System;
    using System.Diagnostics;
    
    public class Example : Node
    {
        public AESContext Aes = new AESContext();
        public override void _Ready()
        {
            string key = "My secret key!!!"; // Key must be either 16 or 32 bytes.
            string data = "My secret text!!"; // Data size must be multiple of 16 bytes, apply padding if needed.
            // Encrypt ECB
            Aes.Start(AESContext.Mode.EcbEncrypt, key.ToUTF8());
            byte[] encrypted = Aes.Update(data.ToUTF8());
            Aes.Finish();
            // Decrypt ECB
            Aes.Start(AESContext.Mode.EcbDecrypt, key.ToUTF8());
            byte[] decrypted = Aes.Update(encrypted);
            Aes.Finish();
            // Check ECB
            Debug.Assert(decrypted == data.ToUTF8());
    
            string iv = "My secret iv!!!!"; // IV must be of exactly 16 bytes.
            // Encrypt CBC
            Aes.Start(AESContext.Mode.EcbEncrypt, key.ToUTF8(), iv.ToUTF8());
            encrypted = Aes.Update(data.ToUTF8());
            Aes.Finish();
            // Decrypt CBC
            Aes.Start(AESContext.Mode.EcbDecrypt, key.ToUTF8(), iv.ToUTF8());
            decrypted = Aes.Update(encrypted);
            Aes.Finish();
            // Check CBC
            Debug.Assert(decrypted == data.ToUTF8());
        }
    }



Methods
-------

+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| void                                          | :ref:`finish<class_AESContext_method_finish>` **(** **)**                                                                                                                                                             |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`get_iv_state<class_AESContext_method_get_iv_state>` **(** **)**                                                                                                                                                 |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`Error<enum_@GlobalScope_Error>`         | :ref:`start<class_AESContext_method_start>` **(** :ref:`Mode<enum_AESContext_Mode>` mode, :ref:`PackedByteArray<class_PackedByteArray>` key, :ref:`PackedByteArray<class_PackedByteArray>` iv=PackedByteArray() **)** |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`update<class_AESContext_method_update>` **(** :ref:`PackedByteArray<class_PackedByteArray>` src **)**                                                                                                           |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Enumerations
------------

.. _enum_AESContext_Mode:

.. _class_AESContext_constant_MODE_ECB_ENCRYPT:

.. _class_AESContext_constant_MODE_ECB_DECRYPT:

.. _class_AESContext_constant_MODE_CBC_ENCRYPT:

.. _class_AESContext_constant_MODE_CBC_DECRYPT:

.. _class_AESContext_constant_MODE_MAX:

enum **Mode**:

- **MODE_ECB_ENCRYPT** = **0** --- AES electronic codebook encryption mode.

- **MODE_ECB_DECRYPT** = **1** --- AES electronic codebook decryption mode.

- **MODE_CBC_ENCRYPT** = **2** --- AES cipher blocker chaining encryption mode.

- **MODE_CBC_DECRYPT** = **3** --- AES cipher blocker chaining decryption mode.

- **MODE_MAX** = **4** --- Maximum value for the mode enum.

Method Descriptions
-------------------

.. _class_AESContext_method_finish:

- void **finish** **(** **)**

Close this AES context so it can be started again. See :ref:`start<class_AESContext_method_start>`.

----

.. _class_AESContext_method_get_iv_state:

- :ref:`PackedByteArray<class_PackedByteArray>` **get_iv_state** **(** **)**

Get the current IV state for this context (IV gets updated when calling :ref:`update<class_AESContext_method_update>`). You normally don't need this function.

**Note:** This function only makes sense when the context is started with :ref:`MODE_CBC_ENCRYPT<class_AESContext_constant_MODE_CBC_ENCRYPT>` or :ref:`MODE_CBC_DECRYPT<class_AESContext_constant_MODE_CBC_DECRYPT>`.

----

.. _class_AESContext_method_start:

- :ref:`Error<enum_@GlobalScope_Error>` **start** **(** :ref:`Mode<enum_AESContext_Mode>` mode, :ref:`PackedByteArray<class_PackedByteArray>` key, :ref:`PackedByteArray<class_PackedByteArray>` iv=PackedByteArray() **)**

Start the AES context in the given ``mode``. A ``key`` of either 16 or 32 bytes must always be provided, while an ``iv`` (initialization vector) of exactly 16 bytes, is only needed when ``mode`` is either :ref:`MODE_CBC_ENCRYPT<class_AESContext_constant_MODE_CBC_ENCRYPT>` or :ref:`MODE_CBC_DECRYPT<class_AESContext_constant_MODE_CBC_DECRYPT>`.

----

.. _class_AESContext_method_update:

- :ref:`PackedByteArray<class_PackedByteArray>` **update** **(** :ref:`PackedByteArray<class_PackedByteArray>` src **)**

Run the desired operation for this AES context. Will return a :ref:`PackedByteArray<class_PackedByteArray>` containing the result of encrypting (or decrypting) the given ``src``. See :ref:`start<class_AESContext_method_start>` for mode of operation.

**Note:** The size of ``src`` must be a multiple of 16. Apply some padding if needed.

.. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`
.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
.. |constructor| replace:: :abbr:`constructor (This method is used to construct a type.)`
.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
.. |operator| replace:: :abbr:`operator (This method describes a valid operator to use with this type as left-hand operand.)`